Etain... What Civinator was saying is that when we click on the Resource Box with the Word None, that Word changes to White Letters with a Dark Background. Otherwise the Word None is Black Letters with the Light Background.
... Probably, this was due to the Unit issue you have corrected now.
Another thing you can do is have a Wonder place Improvements that auto-produce units you want. The AI will build Wonders at the start of the game easier than later, especially when at War.
When the Wonder is built and it places the Improvements that auto-produces the unit you want, the unit can be auto-produced later when ever you want them to be produced.
Simply set the Improvement so it can be built when a specific Resource is gained and set that Resource to appear when you want the Improvement to start producing the Unit.
Now because the Improvements are placed early by a Wonder, the Improvement cannot start producing the Unit without the Required Resource. Therefore, lets say the Improvement produces the Unit every 10 Turns... IF 10 turns have past since the Improvement was placed, when the Resource is gained the Unit will be produced immediately that turn then every 10 turns after.
This is a Good method for establishing Hordes of the same Unit at specific times because they are all produced on the same turn. It also is a way to have the AI and player gain the Units you want them to have at a specific time in the game.